The present invention relates to a process for the manufacture of epoxides by reacting hydrogen peroxide with a compound containing an ethylenic double bond, in the presence of a catalyst.
Epoxides are products having numerous industrial applications, for example in the manufacture of thermosetting polymers which can be used, in particular, as adhesives or surface coatings. Industrially, epoxides are generally manufactured in accordance with complex processes, such as the dehydrochlorination of the corresponding chlorohydrins or the catalytic oxidation of olefines with hydroperoxides or directly with molecular oxygen. To reduce the manufacturing costs and the formation of by-products, and to simplify the processes, it has been proposed to manufacture epoxides by reacting hydrogen peroxide directly with the corresponding olefine in the liquid phase, by virtue of the use of certain specific catalysts. However, the processes known hitherto all have various disadvantages. The productivity of the reactors is low because the reaction is too slow or the solutions to be used are too dilute, the catalysts have an insufficient life and are rapidly deactivated, or the selectivity is poor and many undesirable by-products are obtained, such as diols or alkoxyalcohols, or the separation of the reaction products is difficult. Furthermore, the hydrogen peroxide must frequently be used in the anhydrous form and the reaction mixture must be kept anhydrous. In addition, certain catalysts have an activity which depends greatly on the olefine to be epoxidised. Thus, if selenium oxide is used as the catalyst, diols are obtained with olefines such as cyclohexene, and epoxides are only obtained with very complex olefines of the macrocyclic type (J. Itakura et al., Bull. of the Chem. Soc. of Japan, 1969, 42, pages 1,604 to 1,608).